Table of Contents

## How is decay of heat calculated?

By starting from a known value, based on power history at shutdown, the decay heat generation rate can be calculated for any time after shutdown….Calculation of Decay Heat.

˙Q | = | decay heat (Btu/hr) |
---|---|---|

m | = | mass of coolant (lbm) |

cp | = | specific heat capacity of coolant (Btu/lbm-°F) |

ΔT | = | temperature change of coolant (°F) |

**How do you calculate reactor period?**

The reactor period, T, is defined as that length of time required to change reactor power (or neutron density) by a factor of e. T is sometimes called the “e folding time”, meaning that every T seconds of operation, n/n0 increases by a factor e = 2.718. For the previous example, T is 0.005 s.

**What is the heat from decay of isotopes called?**

Decay heat is the heat released as a result of radioactive decay. This heat is produced as an effect of radiation on materials: the energy of the alpha, beta or gamma radiation is converted into the thermal movement of atoms.

### What is decay heat in a nuclear power plant?

The heat produced by the decay of radioactive fission products after a reactor has been shut down.

**How do you calculate heat from radioactive decay?**

In principle, the energy Q released by radioactive decay is given by the difference between the mass of the parent, mP, and the daughter nuclide(s), mD, multiplied by the square of the velocity of light in vacuum, c0.

**Can reactor periods be negative?**

The reactor period may be positive or negative. If the reactor period is positive, reactor power is increasing. If the reactor period is negative, reactor power is decreasing. If the reactor period is constant with time, as associated with exponential power change, the rate is referred to as a stable reactor period.

#### How is reactor power calculated?

Reaction Rate+

- Ф – neutron flux (neutrons.cm-2.s-1)
- σ – microscopic cross section (cm2)
- N – atomic number density (atoms.cm-3)
- P = RR . Er . V = Ф . Σf . Er . V = Ф . NU235 .
- P – reactor power (MeV.s-1)
- Ф – neutron flux (neutrons.cm-2.s-1)
- σ – microscopic cross section (cm2)
- N – atomic number density (atoms.cm-3)

**Which field is the chosen isotope most useful?**

Radioactive isotopes have many useful applications. In particular, they are central to the fields of nuclear medicine and radiotherapy. In nuclear medicine, tracer radioisotopes may be taken orally or be injected or inhaled into the body.

**Does heat speed up nuclear decay?**

Does radioactive decay depend on temperature? Temperatures do not affect radioactivity at all. This has been tested many times and at extreme temperatures. Temperature is the average vibrational kinetic energy of the molecules of some object.

## What happens if a reactor gets too hot?

According to published reports, backup diesel generators at the power plant failed shortly thereafter, leaving the reactors uncooled and in serious danger of overheating. Without a steady coolant supply, a hot reactor core will continuously boil off the water surrounding it until the fuel is no longer immersed.

**Why does plutonium give off heat?**

All plutonium produces a significant amount of heat due to its radio- active decay. The plutonium that was used in the 1945 Trinity test consisted mostly of Pu-239 and was noticeably warm to the touch. The isotope Pu-238 is responsible for plutonium with a high heat output.

**How do you calculate k effectiveness?**

The “Six-factor formula” is the neutron life-cycle balance equation, which includes six separate factors, the product of which is equal to the ratio of the number of neutrons in any generation to that of the previous one; this parameter is called the effective multiplication factor k, also denoted by Keff, where k = Є …

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